Siege of Paris (978)

The Siege of Paris occurred from September to November 978 when an East Francian army under Holy Roman Emperor Otto the Red and Duke Charles of Lower Lorraine laid siege to the West Francian capital of Paris, which was defended by Lothair of France. The siege was defeated due to illness ravaging the besiegers and the arrival of a French relief army under Hugh Capet, and Otto's rearguard was wiped out at Soissons by Capet.

Background
In 973, Emperor Otto II of Germany appointed his cousin Charles - the brother of King Lothair of France - as Duke of Lower Lorraine, tantamount to securing his defection to East Francia. Lothair was incensed by this, and Otto subsequently convened the imperial diet at Dortmund to declare war on France in July 978; a furious Lothair decided to retaliate by invading East Francia. In August 978, he surprised and plundered the city of Aachen, forcing Otto II's family to flee the royal city. After five days, Lothair decided to return to France, having disgraced the city. In September 978, Otto counterattacked with Charles by invading France, ravaging Reims, Soissons, and Laon and having the Bishop of Metz crown Charles as King of France, forcing Lothair to flee to Paris. Otto promptly laid siege.

Siege of Paris
Lothair and his small, defeated army was besieged in Paris by Otto and Charles' German army, which had faced little resistance during its campaign in Western Europe. The situation was bleak for West Francia until sickness and the arrival of French reinforcements under Hugh Capet forced the Germans to retreat, leaving France as winter arrived. The Germans were unable to ford the Aisne River at Soissons due to flooding, and many died of drowning; one chronicler said, "more died by that wave than by the sword." The French destroyed the German forces and captured their supplies, winning a crucial victory against Emperor Otto's forces. Lothair and Capet chased Otto and Charles back to Aachen and retook Laon, and in 980 a peace treaty was concluded, requiring Lothair to renounce his claims on Lorraine and Otto's recognition of Lothair's son as Louis V of France on his death. Hugh Capet was hailed as the first noble of the Kingdom of France, leading to the rise of the House of Capet in French politics